Risk Factors Identification for Metal Washing Process Based on QOC Matrix the Workers’ Voice and Ergonomic Mapping

In order to determine ergonomic risk factors to be abated during an ergonomic intervention in a metal washing process, two tools were implemented. The questionnaires from the QOC Matrix the workers’ voice was used to build a relationship diagram used to develop an ergonomic mapping. The Ergonomic risk map resulted identified the relationship, between workplace design and non-ergonomic content task. The method used to determine the risk factors was the follow: (a) define the non-ergonomic parameters inside work areas and task content using QOC results, (b) measure the results to categorise them in an ergonomic risk map, (c) using the ergonomic risk map a diagnosis was to carry out, (d) a redesign was proposed to abate non-ergonomic parameters. The activities developed for filling and discharging the washing machine included handling, lifting and carrying a plastic bucket of 40 kg above the shoulders, with an exerting force of 250 N in each lifting, for 120 times. It represented the main ergonomic problem. During the intervention, a new redesign for the working place was proposed; the improving phase incorporated two automatic sulfuric acid dilution system, two automatic mixers and an automatic production line for filling and discharging the washing machine. Consequently, workers change their character of mixers and loaders to the operators of an automatic control panel.